Rotary furnace



G. J. HAGAN July 25, 1933.

ROTARY FURNACE 3 Sheets-Sheet l Filed April 2l G. J. HAGAN ROTARY FURNACE July 25, 1933.

5 sheets-sheetv 2 Filed April 2l I IWI l 1 kw INVENTOR Patented July 25, 1933 GEORGE J'. HAGAN, OF PITTSBURGH, PENNSYLVANIA ROTARY FURNACE Application mea Aprii 21,

My invention relates to furnaces, and

more particularly to rotary furnaces.

During the heating or heat treating of sheets, plates and the like, 'it is desirable, in many cases, to effect individual heating of the different sheets or plates in order to insure absolute uniformity .in successive pieces of metal. It has heretofore been proposed to provide elongated furnaces through which the sheets are passed in succession, the length of the furnace andthe speed of travel of the sheets being such that the desired treatment is obtainedfduring the passage of sheets therethrough. Such furnaces, While satisfactorily performing the intended functions, are open to objection from the standpoint of the amount of lheat radiating surface provided as well asl from the standpoint of the amount of room required for their installation.

It'is one of the objects of the present invention to provide a furnace effective for the individual treatment of shapes of the general c'haracterreferred to, which furnace occupies a minimum amount of room, provides a minimum amount of`radiat1ng wall surface and aifords'a maximum capacity.

In the accompanying drawings there are shown, by Way ofillust-ration only, certain preferred yembodiments of the invention. In the drawings: y

Figure.1 is a view in vertical sectionl of one form of rotary furnace in accordance with my invention; Figure 2 is a viewr in horizontal section taken on the line II--II of Figure l,

Figure 3 is a similar view taken on the line III-III of Figure 1;`

Figure 4 is a view similar to Figure l, on a larger scale, of a modification .of the furnace of my invention; .y

Figure'v is a partial vertical sectional view alongthe line V-V of Figure 4; and

Figure 6 is a diagrammatic view of the Wiring for the sealing means operating motor. y

In the form of the invention illustrated 50 in Figures 1 to 3 both inclusive, which g- 1931. Serial N0. 531,674.

ures are largely diagrammatic by way of illustration only, the furnace is shown as l comprising a rotating crown or cover 1 suitably supported by means of wheels 2. In order to effectively seal `the interior of the furnace against undue heat losses, I have illustrated sand seals 3 underlying the crown and adapted to be supported in any desired manner as by buck-stays or other framework, not shown. Depending from the crown 1 are carriers 4 having their lower edges suitably shaped to cooperate with and carry sheets 5to be treated in the-fun nace. Below the sheets is la perforated hearth 6-`lying above a'suitable combustion 65 chamber or chambers 7. l

The furnace proper is enclosed by anouter substantially circular wall 10 'having any desired number and arrangement of door openings'9 through which the sheets'may 70 be charged into or removed'from the furnace.' Extending through the outer Wall are burner openings 8 communicating with the combustion chambers 7 beneath the hearth 6; Concentric with the outer wall 10 is an 75 inner wall 11, lthe -walls being spaced'a distance suchl that sheets of the desired size may be accommodated. Extending' between and supporting the respective walls 10 and 11 are bridge Walls 12 dividing the combus- 30 tion space into a series of individual chambers'closed at their lower ends by a bottom wall13. Y y y During the operation of the furnace, the heated gases and products of combustion from the combustion chambers 7 will pass upwardly through the openings yin the hearth 6 and thus raise the sheets 5 to the desired temperature. Y Byv reference more yparticularly to lFigure 1, it will be noted 9 that the sand seals 3 are so disposed as to cooperate both with the inner and the outer walls. Extending into the seals, which are conveniently formed in channels 14 and 15, are plates 16 and 17 which arepreferably 95 supported by the Iwheels 2 and which in turn carry the crown'l. The rims of the channels 14 and 15 in turn preferably serve as circular trackways for the Wheels, thus insuring a predetermined relationshipV be- 10 tween the sealing plates and the seals at all times during the rotation of the crown.

In the embodiment of the invention illustrated, the carriers 4 are shown as having outwardly turned lower edges 18 adapted to engage similarly ofl'set edge portions 19 on the sheets 5. In loading the carriers` the sheets to be treated are slid onto the carriers in a lengthwise direction through a suitable opening 9. If the charging and discharging is effected through a common door opening, it will be apparent that before sliding a new sheet into position. a previously treated sheet is removed therefrom, while if spaced door openings are utilized. the sheets are removed at one opening and charged into the furnace through a succeeding opening.

In the construction illustrated in Figure 2, two such openings are shown. although it will be understood that the invention is not limited to any particular number or arrangement of door openings. The desired discharging and charging operations having been effected, the rotary crown is rotated a distance equal to the distance between adjacent sheets, whereupon the discharging and charging operations are again repeated. A furnace of the structure shown readily accommodates itself to a large number of sheets each individually supported, and enables the furnace to be utilized for annealing, normalizing or the like, or for the baking, drying or hardening of suitable coating materials such as enamel, varnish or paint. The rapidity of rotative movements is made such that each sheet during a complete or partial revolution of the rotary crown is `subjected to and receives the desired treatment.

In the embodiment of the invention illustrated in Figure 4, the rotary crown 21 is shown as comprising a series of individual blocks of refractory material,with alternate blocks directly supported from a structural framework 22. This framework 22 is symmetrically positioned above a central sleeve 23 through which extends a pivot shaft 26. Extending between the upper end of the sleeve 23 and the outer ends of the members constituting the structural framework are supporting rods 27 having means 28 for adjusting their length and properly positioning the framework.

Forming a hub for the framework 22 is a circular channel 29 encircling the sleeve 23 and provided in its lower face with a. suitable ball race for cooperation with an antifriction bearing 30. This bearing is in turn supported by a lower plate 24 carried by a lifting ram 25.

For driving the rotary crown there is provided a pinion 31, adapted to be driven from a suitable source of power, not shown, and meshing with a rack 32 suitably secured to and surrounding the structural framework of the crown. Mounted between the inner periphery of' the rack 32 and the outer ends of the members 22 is a plurality of flanged wheels cooperating with a circular track 34. This track is illustrated as supported independently of the furnace by a. suitable framework 35. this heilig generally similar to the supporting means for the channels 14 and 15 as before described.

Extending downwardly from the framework 22 and embracing the crown 21 are inner and outer flanges 36 and 3T cooperating at their lower ends with a sand seal 38 formed in inner and outer channels 39 and 40. These channels are herein illustrated as being carried directly by the walls 41 and 42 of the furnace. Extending between the furnace walls is a suitablel floor 43, thus providing a substantially enclosed annular heating or treating chamber.

Depending from the crown 2l are carriers 44 for engaging sheets 45. the construction of the carriers being similar to that before described. For heating the sheets, I have illustrated electric heating elements 4G suitably positioned within the. furnace and preferably on three sides of the annular chamber 47 for supplying heat to the sheets from a plurality of sides. Access to the furnace for charging and discharging purposes is provided by means of one or more openings 48 through which the sheets may be individually inserted or removed.

In the absence of special sealing means, it will be apparent that when the doors 49 cooperating with the respective door openings 48 are opened, the entire interior of the furnace would be subjected either to loss of heat or to the influx of relatively cooler atmospheric air. To preclude such a condition, I may provide adjacent each of the door openings a pair of sealing plates 50 vertically movable through openings 5l in the bottom 43 of the furnace. During rotation of the furnace with the doors 49 closed, the sealing plates are adapted to be lowered to permit the passage of the sheets 45 thereover, while upon charging and discharging the furnace, at which time rotation of the crown is stopped, the sealing doors are raised on opposite sides of a door opening 'so as to permit a sheet to be charged into or discharged from the furnace. For effecting such a movement of the sealing means in timed relation to the rotation of the crown 21 there is shown a shaft 52 carrying gears 53 meshing with racks 54 on the lower end of one of the sealing plates.

Driven by the gear 53 is a pinion 53 meshing with similar racks 55 on the lower end of the other of the sealing plates. By reason of this construction, it will be apparent that when the gear 53 is rotated in one direction, the plates will be simultaneously raised, while upon rotation in the opdividual sheet.

posite direction they will be simultaneously lowered. Rotation of the shaft 52 is obtainable by means of a motor 56 operatively connccted to the shaft through a yfriction coupling 57. Vired to the motor 56 is a-pair of leads 58 effective when energized for insuring rotation of the motor in one direction, a second pair of leads 59 being similarly effective when energized for insuring rotation in the opposite direction. Rotatable in synchronism with the pinion 31 is a commutator 60 having conducting segments 61jand 62 effective respectively for closing the circuits 58 and 59 in succession.

Thus, upon commencement of rotation of the crown 22 the segment 62 will close the circuit 59 and lower the sealing plates 50, while just prior to cessation of rotation of the crown 21 the segment 61 will energize the circuit 58 for raisingthe sealing doors. From the previousdescription, it will be understood that any desired numberof pairs of sealing doors may be provided depending upon the numberand,arrangement of door openings in the furnace, each pair of sealing doors being effective for sealing off a portion of the furn-ace chamber allotted to an in- Due to the fact that a large number of sheets may be substantially simultaneously treated while maintained in relatively closely adjacent side byv side relationship, it will be apparent that a maximum capacity for heat treating or other purposes is available. At the same time, the length of the outer wall of a furnace in accordance lwith the present invention is materially lessthan the overall length of one wall of a straight line furnace as heretofore provided. Itis likewise apparent that the length of the inner wall and its heat radiating area are likewise `maintained at a minimunn .The furnace therefore adapts itself to thel use of electrical heating units without incurring high operating costs.

Reference hask already been made to the lifting ram 25 which supports the anti-friction mounting for the crownv of the furnace. This ram is herein illustrated as being of the fluid pressure or hydraulic type effective when energized for quickly raising the crown bodily from its sealing relation with the furnace. It will be understood, however, that other forms of lifting means may be utilized for accomplishing the same purpose. By the use of such a construction, it is possible to quickly raise the roof either for making repairs to the furnace or for charging the same in case articles other than sheets are to be heated or heat treated therein. This combination of a rotatable crown with means for quickly raising the same to permit access to the interior of the furnace constitutes a further advantage of the invention.

While I have herein described my invention as being particularly useful in the treating of sheets, it is to be clearly understood that this is by way of example only,

said chamber, and retractible spaced sealing plates effective for providing transverse partitions in the chamber.

f 2. In ak rotary furnace, an annular treating chamber, a rotating cover having means thereon within the furnace for individually supporting sheets in a radial position within said chamber, spaced sealing plates movable transversely into and out of thechamber, and means for operating said sealing means in timed relation to the o' eration of said cover to project and with raw the sealing plates at predetermined points with respect to the movement of the cover.

3. In a furnace, a substantially annular v treating chamber, a rotatable cover spanning the top of the heating chamber and constituting an upper closure for said chamber, a plurality of substantially radially eX- tendinghook-like carriers depending, from said cover and adapted to individually support articles within said chamber, and means through the side walls of said chamber permitting access 'to said 'carriers for charging and discharging purposes.

4. In a furnace, a substantially annular treating chamber, a rotatable cover constituting an upper closure for said chamber, a

plurality of substantially "radially extendingjcarriers depending from said cover and adapted to individually support articles within said chamber the chamber having an opening through the side walls of said chamber permitting access to said carriers for charging and discharging purposes, and radially disposed sealing means movable into and out of the chamber and effective on opposite sides of said openings.

5. In a furnace, a substantially annular treating chamber, rotatable means for individually supporting articles to be treated within said chamber, spaced plates movable transversely into and out of said chamber, and means for operating said spaced plates in timed relation with respect to the operation of the furnace.

6. In a rotary furnace, a substantially annular treating chamber, heating means for -said chamber, a rotating cover for sealing said chamber, article supporting means suspended from the cover into the heating chamber, and means for bodily raising said cover from cooperative relation with the furnace. j

7. In a rotary furnace, a substantially annular treating chamber. a rotating cover cooperating with said chamber, article supporting means suspended from the cover into the heating chamber, an anti-friction support for said cover, and vertically movable lifting means carrying said support.

8. In a rotary furnace, a substantially annular treating chamber, a rotating cover for said chamber, material supporting means carried by said cover and projecting into the heating chamber, and means for effecting vertical movement of said cover.

9. In a rotary furnace, a substantially annular treating chamber, heating means for said chamber, material supporting means for said chamber, article supporting means suspended from the cover into the heating chamber, a rotatable cover for said chamber,

and means for vertically moving said cover.

10. In a rotary furnace, an annular treating chamber, heating means for` said chamber, a cover for said chamber, sealing means between said cover and chamber, article supporting means suspended from the cover into the heating chamber, and means for vertically raising said cover to break said sealing means and permit access to the inteiior of the chamber.

11. A furnace for heat treating individually supported articles, comprisingA a substantially annular treating chamber having a bottom and concentric side Walls andv open at its top, a rotating refractory-lined cover spanning the open top of the chamber, and means depending from said cover and entirely below the refractory for maintaining the articles to be treated'in the desired position Within said chamber.

12. In a furnace, a substantially annular treating chamber, rotatable means for individually supporting articles to be treated within said chamber, spaced plates for sealing off a predetermined article from the remainder of said chamber, and means for operating said sealing plates in timed relation to the operation of said cover to project and Withdraw the sealing plates at predetermined points with respect to the movement of the cover.

13. A furnace of the class described comprising an annular heating chamber having concentric inner and outer walls and open at its top, a cover having a refractory lining spanning the open top of the chamber, a sealing trough around the outside of the outer wall, a sealing trough around the outside ofthe inner wall, sealing means on the cover extending into the respective troughs, the seals thus being spaced outside the Walls of the heating chamber, and supporting means on the cover projecting into the heating chamber for supporting articles to be heated.

14. A furnace of the class described comprising an annular heating chamber having concentric inner and outer Walls and open at its top, a cover having a refractory lining spanning the open top of the chamber. a sealing trough around the outside of the outer Wall, a sealing trough around the outside of the inner Wall, sealing means on the cover extending into the respective troughs, the seals thus being spaced outside the Walls of the heating chamber, supporting means on the cover projecting into the heating chamber for supporting articles to be heated, spaced sealing plates movable transversely into and out of the chamber, and means for operating said sealing plates in timed relation to the operation of said cover.

15. In a furnace for the heat treating of sheets and similar articles, an annular treating chamber, a carrier at the top of the chamber having radially extending supporting means thereon for suspending the sheets vertically in a radial position, said furnace having an opening in the side Walls thereof through Which sheets may be inserted and/0r removed from said radially extending sup- 

